Climate-smart agriculture practice promotes sustainable maize production in northeastern China: Higher grain yield while less carbon footprint

Maize production is facing multiple challenges toward increasing crop productivity, enhancing resource utilization, and mitigating climate change nowadays. Climate-smart agriculture (CSA) is an emerging concept, which pursues the synthesis of higher crop productivity, lower carbon emissions, and improved soil resilience to the climate change. However, few studies have been done to evaluate the productivity and environmental consequences following the CSA of maize production. Herein, the effects of CSA practice on maize yield, nitrogen use efficiency (partial factor productivity, PFPN), soil organic carbon (SOC) sequestration, and carbon footprint (CF) were evaluated based on a nine-year in-situ field experiment in northeastern China. The experiment followed a randomized block design with three treatments including in traditional farmers' practices (FM), optimized agronomic practices (OPT, aiming to high grain yield and PFPN), and climate-smart agriculture practices (CSA, aiming to higher grain yield, PFPN, SOC stock, while lower CF). Compared with FM, OPT and CSA practices significantly increased grain yield and PFPN by 25.0%-30.1% and 92.2%-100.2% on average of experimental duration, respectively. CSA practice had significant higher global warming potential (GWP) but equivalent global warming potential intensity (GWPI) than these of FM and OPT practices during 2016 and 2017. Meanwhile, CSA practice also achieved the highest SOC sequestration in 0-40 cm soil depth compared to other treatments. Consequently, CF per hectare (CFa) of CSA significantly decreased by 41.4% on average than that of FM mainly due to higher SOC sequestration. Concerning the profit of cropping system, CSA had the highest net ecosystem economic budget (NEEB) of 2090.62 $ ha-1 among the treatments. Overall, CSA practice showed advantages in promoting maize yield while reducing carbon footprint by integrated agronomic management (e.g. dense planting, subsoiling tillage, manure amendments, nitrogen fertilizer optimization, and so on), which could be regarded as a promising practice towards food security and carbon emission mitigation.